@Nathalie *********
you can apply for your yearly extension in Pattaya if you submit address (TM30, TM28 maybe - , not sure Pattaya requires). And also you need to provide all required documents. Some bank letters & documents, etc. At some immigration office, you may need to show a long-term contract or other documents of your accommodation, too. Check Pattaya immigration for their requirements first - as soon as possible.